Summary: Size effects on the thermodynamics of melting
Yinon Ashkenazy
Racah Institute of Physics
The Hebrew University of Jerusalem
The effect of particle size at the nanometer scale on melting temperature, as shown in
a series of experiments done over the past two decades, depends on various factors
such as particle shape and confinement. Current models for this modification depend
not only on surface or interface energies but also on the specific melting mechanism.
Therefore, this system can serve as a model to study the nature of the solid liquid
phase transition itself. This process is of interest since the specific nature of the solid-
liquid transition, namely its underlying atomistic mechanism, remains as of today a
mystery even in the bulk.
In this talk I will review experimental observations and existing models for the
modifications of the melting or freezing temperature with size as well as observations
regarding the metastable branches of these transitions. Using initial results from
molecular dynamics calculations of the melting process, together with vibrational
density of states calculations, I will discuss what can be deduced on the properties of
the underlying atomistic mechanism of melting. Results will be linked to a defect
based mechanism of melting.